Unrecognized species diversity and endemism in the cichlid genus Bujurquina (Teleostei: Cichlidae) together with a molecular phylogeny document large-scale transformation of the western Amazonian river network and reveal complex paleogeography of the Ecuadorian Amazon

Repeated ecomorphological divergence in Bujurquina (Teleostei: Cichlidae) body shape

“…Molecular-based dating and biogeographic analyses (Musilová et al 2015, Říčan et al 2022) support the hypothesis that most of the genus' evolution occurred throughout the period of major Amazonian river network reorganisation. Both molecular and colouration-pattern data demonstrate a division of the genus into two main phylogenetic groups, the Southern and Northern groups, that divide within the present Ucayali basin of Peru (Říčan et al 2022). These two Bujurquina lineages are characterised by different colouration patterns, chiefly on the dorsal fin, which is unpatterned in the Southern group but ornamented in the Northern group.…”

“…Among Amazon freshwater fishes, the cichlid fishes fulfil all the above requirements. Moreover, cichlids are one of the most important Neotropical fish groups, being the dominant group of larger-sized fishes in Middle America (Myers 1966, Bussing 1976, 1985, Říčan et al 2013, 2016) and the third richest family of fishes in South America (Van der Sleen & Albert 2018).…”

“…Within the cichlid fishes, the genus Bujurquina Kullander, 1986 represents the best model group for studying Andean and western Amazon landscape evolution and its direct influence on the formation of biodiversity (Říčan et al 2022). Bujurquina species are highly philopatric, show small-scale endemism, strong adaptation to local environmental conditions, and are highly diverse in the lowlands and Andean foothills (unlike Apistogramma , the other species-rich genus of the western Amazon).…”

“…Bujurquina species are highly philopatric, show small-scale endemism, strong adaptation to local environmental conditions, and are highly diverse in the lowlands and Andean foothills (unlike Apistogramma , the other species-rich genus of the western Amazon). Furthermore, it is the only cichlid genus whose geographic distribution and highest diversity is centred in the western Amazon and whose distribution and endemism follows the putative course of the paleo-Amazon (Kullander 1986, Říčan 2017, Říčan et al 2022). Consequently, Bujurquina species have a distribution unlike any other large South American cichlid genera, which generally (not Apistogramma ) show the highest diversity and endemism in the older eastern Amazon within the Brazilian and Guiana shield regions (Stawikowski & Werner 1998, 2004, Kullander et al 2018, Van der Sleen & Albert 2018, Říčan et al 2021).…”

“…Bujurquina distribution follows an arc from Argentina, Paraguay and Bolivia in the south, through its highest currently known centre of diversity and endemism in Peru (Kullander 1986) and Ecuador (Říčan et al 2022), and continues to the north through Colombia and Venezuela (Kullander 1986, Stawikowski & Werner 1998, Van der Sleen & Albert 2018). Molecular-based dating and biogeographic analyses (Musilová et al 2015, Říčan et al 2022) support the hypothesis that most of the genus' evolution occurred throughout the period of major Amazonian river network reorganisation. Both molecular and colouration-pattern data demonstrate a division of the genus into two main phylogenetic groups, the Southern and Northern groups, that divide within the present Ucayali basin of Peru (Říčan et al 2022).…”